Pinnacle Engineering Anti-inversion Shackle. This is a great shackle that we run on almost all of the Cruisers here. They are approximately 1" greater than the stock for 1/2 inch lift. Works great with all suspensions. Comes with standard bolts, available for greaseable at additional costs. Sold each.  Shackles have 5/8" bolts, they are tight on early (80 down Cruisers) and looser on late (81 up Cruisers)